title: Synthesis of 2,3-butanediol by Synechocystis sp. PCC6803 via heterologous expression of a catabolic pathway from lactic acid- and enterobacteria.
abstract: The direct and efficient conversion of CO2 into liquid energy carriers and/or bulk chemicals is crucial for a sustainable future of modern society. Here we describe the production of 2,3-butanediol in Synechocystis sp. PCC6803 expressing a heterologous catabolic pathway derived from enteric- and lactic acid bacteria. This pathway is composed of an acetolactate synthase, an acetolactate decarboxylase and an acetoin reductase. Levels of up to 0.72 g/l (corresponding to 8 mmol/L) of C(4) products, including a level of 0.43 g/l (corresponding to 4.7 mmol/L) 2,3-butanediol production are observed with the genes encoding these three enzymes integrated into the cyanobacterial genome, as well as when they are plasmid encoded. Further optimization studies revealed that Synechocystis expresses significant levels of acetolactate synthase endogenously, particularly under conditions of restricted CO2 supply to the cells. Co-expression of a soluble transhydrogenase or of an NADPH-dependent acetoin reductase allows one to drive the last step of the engineered pathway to near completion, resulting in pure meso-2,3-butanediol being produced.
authors.affiliation: Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands; Netherlands Institute for Systems Biology, University of Amsterdam, Amsterdam, The Netherlands; Towards BioSolar Cells Consortium, The Netherlands.
authors.forename: Philipp E
authors.initials: PE
authors.lastname: Savakis
authors.forename: S Andreas
authors.initials: SA
authors.lastname: Angermayr
authors.forename: Klaas J
authors.initials: KJ
authors.lastname: Hellingwerf
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D002072:Butylene Glycols / Q000378:metabolism*; D021902:Enterobacter aerogenes / Q000201:enzymology / Q000235:genetics; D015870:Gene Expression; D007934:Leuconostoc / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D046939:Synechocystis / Q000201:enzymology / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002072:Butylene Glycols; D011994:Recombinant Proteins; C026978:2,3-butylene glycol
keywords: Butanediol; Catabolic pathway; Cell factory; Cyanobacteria; Metabolic engineering